But it is worth considering what may be the
factors exacerbating the disparity.

In his recent commentary, Byron Wien, the vice chairman of
Blackstone Advisery Partners, offered some thoughts as to why the
inequality gap in the US has grown wider since 2000.

He argues that it has something to do with the fact that the
wealthy own homes and stocks, while the less affluent do not.

"How did [the widening inequality gap] happen? Wealthy
people own the expensive real estate where they live, and may
have other expensive properties as well. They are also more
likely to own common stocks. Both the real estate and the
equities have appreciated," he wrote.

"The less affluent tend to be renters with limited equity
holdings. Many live paycheck to paycheck and their personal
wealth has not appreciated significantly," he added.

Wien also argued in his commentary that "in spite of
the wealth disparity, inequality does not seem to be a major
political issue at this time." However, given the rise of
populist movements both in the United States and across the
world, at a time when inequality has grown amid increased
globalization, some
could argue that there might be a correlation between
rising inequality and shifts in the political climate.

In any case, taking a look at the data on US inequality is pretty
eye-opening.

Back in November, Deutsche Bank's chief international
economist Torsten Sløk sent around a chart showing the share
of US household wealth by income
level. Notably, the top 0.1% of households
now hold about the same amount of wealth as the bottom
90%.

The Gini
coefficient is a measurement of the income distribution
within a country that aims to show the gap between the rich and
the poor. The number ranges from zero to one, with zero
representing perfect equality (everyone has the same income) and
one representing perfect inequality (one person earns the entire
country's income and everyone else has nothing.) A higher Gini
coefficient means greater inequality.

Developed-market economies such as those in Germany, France, and
Sweden tend to have a higher GDP per capita and lower Gini
coefficients.

On the flip side, emerging-market economies in countries like
Russia, Brazil, and South Africa tend to have a lower GDP per
capita but a higher Gini coefficient.

The US, however, is a big outlier. Its GDP per capita is on par
with developed European countries like Switzerland and Norway,
but its Gini coefficient is in the same tier as Russia's and
China's, both of which are emerging markets.

This is another informal measure of inequality: A handful
of hyper-affluent people can skew a mean upward while not
changing the median very much. That means a higher degree of
inequality will most likely be reflected in a bigger spread
between a mean and median income.

As you can see below, the gap between the two has been
widening over time, which suggests that income inequality has
been growing.